The present invention relates to an apparatus for recirculating the blow-by gases in the crankcase of an internal combustion engine back to an air-mixture intake passage such as an intake manifold.
When the fuel is ignited and exploded in an engine combustion chamber, gases are produced therein and the pressure in the combustion chamber is increased. Some of the gases are forced under the increased pressure to flow through the gap between the piston and the cylinder wall into the crankcase. As this process is repeated during operation of the engine, these blow-by gases are accumulated to develop a high pressure in the crankcase and caused to leak between the crankcase and the oil pan into the atmosphere as undesired air pollutants.
To solve the above problem, there have been employed blow-by gas recirculating apparatus, known as a positive crankcase ventilation (PCV) system, for guiding unburned gases that have leaked into the crankcase back to the combustion chamber as blow-by gases and introducing air into the crankcase for crankcase ventilation.
Some blow-by gas recirculating apparatus include a breather chamber disposed in the cylinder head and connected to the air cleaner. During engine operation, air is supplied via the breather chamber into the crankcase.
In such blow-by gas recirculating apparatus, the pressure in the air cleaner is lower than that in the breather chamber while the engine is rotating at high speeds, causing blow-by gases to flow from the breather chamber into the air cleaner. The blow-by gases contain a large amount of oil mist as well as unburned gases, and such oil mist would be attached to the filter element in the air cleaner, thus contaminating the air filter.
U.S. Pat. No. 4,156,406 issued on May 29, 1979 discloses a gas-oil separator for separating oil and contaminants from gas-oil mixtures in an internal combustion engine. U.S. Pat. No. 4,345,573 issued on Aug. 24, 1982 discloses a blow-by gas treating and controlling system.